Crossness Wastewater Treatment Works

Crossness WWTW, SE London. This was a £220m project for Thames Water. As part of the TTQI (Tidal Thames Quality Improvement) strategy, Crossness’ main scope was to provide 44% additional capacity to fully treat increasing storm flows and all to a tighter consent. WDL were asked to provide contracting services from conceptual design to as built stage.

Based for the most part on site in SE London, we completed the mechanical design/layout drawings for the majority of the new works and some of the original (see brief scope below indicating the range of plant for which we produced full GA drawings). All design & drawings completed to Thames Water specifications – of which we have in-depth knowledge – British Standards & WIMES.

Our drawings were used to assist the Civil design sub-contractor with their detailed design and for MEICA tendering. Post MEICA sub-contract awards, we were relied upon to check and comment on the Suppliers’ detailed design deliverables, which involved frequent liaison on site and meetings to ensure correct design, specification compliance and interfacing.

Latterly, following more liaison to obtain accurate and compliant drawings, we incorporated the Suppliers’ as built drawings into our Mechanical GAs for final submission to Thames Water.

The brief scope included:

The complete refurbishment of the inlet pumping station, construction of a new, elevated preliminary treatment works comprising connection to the original works, fine screens and constant velocity grit channels which connect, via screw conveyors and/or pipework, to the screenings conditioning and grit washing area/building.

A new wastewater treatment stream includes [rectangular] primary sedimentation, aeration and final settlement tanks, sludge storage and thickening equipment all with associated pumping stations and distribution chambers, access platforms etc.

Extensive refurbishment and upgrading of the original works, comprehensive power management improvements, additional odour control for elements new and old and the installation of a large wind turbine.